/**
 * @author       Richard Davey <rich@photonstorm.com>
 * @copyright    2018 Photon Storm Ltd.
 * @license      {@link https://github.com/photonstorm/phaser/blob/master/license.txt|MIT License}
 */

var GetCenterX = require('../../bounds/GetCenterX');
var GetTop = require('../../bounds/GetTop');
var SetCenterX = require('../../bounds/SetCenterX');
var SetTop = require('../../bounds/SetTop');

/**
 * Takes given Game Object and aligns it so that it is positioned in the top center of the other.
 *
 * @function Phaser.Display.Align.In.TopCenter
 * @since 3.0.0
 *
 * @param {Phaser.GameObjects.GameObject} gameObject - The Game Object that will be positioned.
 * @param {Phaser.GameObjects.GameObject} alignIn - The Game Object to base the alignment position on.
 * @param {number} [offsetX=0] - Optional horizontal offset from the position.
 * @param {number} [offsetY=0] - Optional vertical offset from the position.
 *
 * @return {Phaser.GameObjects.GameObject} The Game Object that was aligned.
 */
var TopCenter = function (gameObject, alignIn, offsetX, offsetY)
{
    if (offsetX === undefined) { offsetX = 0; }
    if (offsetY === undefined) { offsetY = 0; }

    SetCenterX(gameObject, GetCenterX(alignIn) + offsetX);
    SetTop(gameObject, GetTop(alignIn) - offsetY);

    return gameObject;
};

module.exports = TopCenter;
